Oregon Zoo releases critters

The Oregon Zoo released 18 of its tiniest critters Tuesday Oregon silverspot butterflies reared at the zoo. It was the culmination of a summer-long release of 850 of the endangered butterflies, as part of a strategy to stabilize their population.

Were putting more butterflies into the ecosystem in hopes that theyll breed with wild butterflies and avoid local extinction, says Mary Jo Andersen, the zoos lead butterfly keeper.

Once common along the Oregon coast, the Oregon silverspot was listed as threatened by the U.S. Fish and Wildlife Service in 1980  one of two Oregon butterflies listed as threatened or endangered under the U.S. Endangered Species Act. By the 1990s, the species could only be found in four locations in the state.

In addition to releasing pupae, the Oregon Zoo raises and plants thousands of early blue violets, which serve as habitat for the Oregon silverspot.

When the caterpillars hatch, theyre tiny  just about the size of Abe Lincolns nose on a penny, Andersen says. But they will eat more than 300 nickel-sized violet leaves before theyre ready to pupate.

The zoo works in partnership with Seattles Woodland Park Zoo, the Washington Department of Fish and Wildlife, Mission Creek Corrections Center for Women and the Portland-based Xerces Society for Invertebrate Conservation to help rear endangered butterflies and release them into the open.

Steve Law can be reached at 503-546-5139 or This email address is being protected from spambots. You need JavaScript enabled to view it.